Microcontroller based Automatic Power Factor Correction for Industrial Power use to Minimize Penalty

In this proposed system, two zero crossing detectors are used for detecting zero crossing of voltage and current. The project is meant to attenuate penalty for industrial units using automatic power factor correction unit. The microcontroller utilized during this project belongs to 8051 family. The interruption between the zero-voltage pulse and zero-current pulse is duly generated by suitable operational amplifier circuits in comparator mode is fed to 2 interrupt pins of a microcontroller. The program takes over to actuate appropriate number of relays from its output to bring shunt capacitors into load circuit to urge the facility factor till it reaches near unity. The capacitor bank and relays are interfaced to the microcontroller employing a relay driver. It displays delay between this and voltage on an LCD. Furthermore, the project is enhanced by using thyristor control switches rather than relay control to avoid contact pitting often encountered by switching of capacitors because of high in rush current.

Intermittent Arc Fault Detection And Location For Aircraft Power Distribution System

This thesis addresses a non-destructive diagnostic method for intermittent arc fault detection and location. Intermittent arc faults appear in aircraft power systems in unpredictable manners when the degraded wires are wet, vibrating against metal structures, or under mechanical stresses, etc. They could evolve into serious faults that may cause on-board fires, power interruptions, system damage and catastrophic incidents, and thus have raised much concern in recent years. Recent trends in solid state power controllers (SSPCs) motivated the development of non-destructive diagnostic methods for health monitoring of aircraft wiring. In this thesis, the ABCD matrix (or transmission matrix) modeling method is introduced to derive normal and faulty load circuit models with better accuracy and reduced complexity compared to the conventional differential equation approach, and an intermittent arc fault detection method is proposed based on temporary deviations of load circuit model coefficients and wiring parameters. Furthermore, based on the faulty wiring model, a genetic algorithm (GA) is proposed to estimate the fault-related wiring parameters, such as intermittent arc location and average intermittent arc resistance. The proposed method can be applied to both the alternating current (AC) power distribution system (PDS) and direct current (DC) PDS. Simulations and experiments using a DC power source have been conducted, and the results have demonstrated effectiveness of the proposed method by estimating the fault location with an accuracy of +/- 0.5 meters on 24.6 meters wire. Unlike the existing techniques which generally requires special devices, the proposed method only needs circuit voltage and current measurement at the source end as inputs, and is thus suitable for SSPC-based aircraft PDS.

Intermittent Arc Fault Detection And Location For Aircraft Power Distribution System

This thesis addresses a non-destructive diagnostic method for intermittent arc fault detection and location. Intermittent arc faults appear in aircraft power systems in unpredictable manners when the degraded wires are wet, vibrating against metal structures, or under mechanical stresses, etc. They could evolve into serious faults that may cause on-board fires, power interruptions, system damage and catastrophic incidents, and thus have raised much concern in recent years. Recent trends in solid state power controllers (SSPCs) motivated the development of non-destructive diagnostic methods for health monitoring of aircraft wiring. In this thesis, the ABCD matrix (or transmission matrix) modeling method is introduced to derive normal and faulty load circuit models with better accuracy and reduced complexity compared to the conventional differential equation approach, and an intermittent arc fault detection method is proposed based on temporary deviations of load circuit model coefficients and wiring parameters. Furthermore, based on the faulty wiring model, a genetic algorithm (GA) is proposed to estimate the fault-related wiring parameters, such as intermittent arc location and average intermittent arc resistance. The proposed method can be applied to both the alternating current (AC) power distribution system (PDS) and direct current (DC) PDS. Simulations and experiments using a DC power source have been conducted, and the results have demonstrated effectiveness of the proposed method by estimating the fault location with an accuracy of +/- 0.5 meters on 24.6 meters wire. Unlike the existing techniques which generally requires special devices, the proposed method only needs circuit voltage and current measurement at the source end as inputs, and is thus suitable for SSPC-based aircraft PDS.

A Simple Method to Determine the Performance of Two-Coil Wireless Power Transfer Systems without Direct Output Measurement

Two-coil wireless power transfer (WPT) systems are composed of two circuits tuned at the same resonance frequency, one containing the source, and other containing the load, both connected to each other by the mutual inductance. The power delivered to the load circuit (Po) divided by the total power supplied by the source (PT) and by the maximum ideal amount of power which can be delivered to the load circuit are usual figures of merit known as efficiency (n) and power transfer capability (P*), respectively. Additionally, it can be defined a third figure of merit (I*) as the power dissipated at the source circuit divided by PT. It has been recently demonstrated that n and P* are related to I* . In this paper, it is presented a simple method to monitor I*, allowing consequently the determination of n and/or P* without any direct measurement at the load circuit. The qualities and limitations of the proposed method are discussed in details. Practical results are included to verify the proposal.

A Simple Method to Determine the Performance of Two-Coil Wireless Power Transfer Systems without Direct Output Measurement

Two-coil wireless power transfer (WPT) systems are composed of two circuits tuned at the same resonance frequency, one containing the source, and other containing the load, both connected to each other by the mutual inductance. The power delivered to the load circuit (Po) divided by the total power supplied by the source (PT) and by the maximum ideal amount of power which can be delivered to the load circuit are usual figures of merit known as efficiency (n) and power transfer capability (P*), respectively. Additionally, it can be defined a third figure of merit (I*) as the power dissipated at the source circuit divided by PT. It has been recently demonstrated that n and P* are related to I* . In this paper, it is presented a simple method to monitor I*, allowing consequently the determination of n and/or P* without any direct measurement at the load circuit. The qualities and limitations of the proposed method are discussed in details. Practical results are included to verify the proposal.

ANALYSIS OF ELECTRICAL LOSSES IN THE MUTUAL LOAD CIRCUIT OF ASYNCHRONOUS MOTORS USING FREQUENCY CONVERTERS

Обоснована актуальность разработки испытательных станций для асинхронных двигателей с применением метода взаимной нагрузки. Цель исследования - оценить потери, вызванные генерацией высших гармонических составляющих на выходе преобразователей частоты. Осуществлено математическое моделирование процесса испытания асинхронных машин. Дополнительные потери, обусловленные несинусоидальностью напряжения, составили 6-10 % для машин различной мощности. Даны рекомендации по применению полученных результатов в процессе разработки испытательных станций.